The present invention relates, in general, to interconnects and, more particularly, to optical interconnects.
Optical fiber technology is used in a variety of applications such as telecommunication, computer, and medical applications. An important aspect of optical fiber technology is the coupling of an optical fiber to an optoelectronic device for transmitting information conducted by the optical fiber.
Optical fibers are typically arranged in a bundle and protected by a sheath. Such a bundle of optical fibers is often referred to as an optical cable. The light receiving and emitting ends of the optical fibers are housed in fiber ferrules. The fiber ferrule at the light receiving end of the bundle is coupled to a light emitting device via an optical interface unit. Likewise, the fiber ferrule at the light emitting end of the bundle is coupled to a light detecting device via an optical interface unit.
A drawback of these systems is the large number of optical interface or coupling points through which the optical signals pass. In currently available systems, optical signals pass through at least four interfaces, i.e., interfaces between the optical interface units and the light emission and detection devices and interfaces between the optical interface units and the fiber ferrules. Each time the optical signal passes through an optical interface, a portion of the signal is lost, thereby degrading the quality of the optical signals transmitted in optical fibers.
In addition, for convenience and space efficiency, it is generally preferred to arrange optical fibers parallel to a circuit board. Therefore, when a vertical light emitting or detection device such as, for example, a vertical cavity surface emitting Laser (VCSEL) or photodetector is coupled to optical fibers, the chip that includes the vertical light emitting or detection device is mounted perpendicular to the circuit board. The perpendicular orientation of the vertical light emitting or detection device can be accomplished by several means, e.g., flexible circuits using tape automated bonding (TAB), electrically patterned submounts connected to the circuit board, etc. However, flexible circuits and submounts are additional components that are often expensive. Further, flexible circuits and submounts increase the electronic paths of the light emitting or detection devices and, therefore, degrade their performance.
Accordingly, it would be advantageous to have an optical coupler and a method for coupling an optical fiber to an optoelectronic device that reduce the signal loss along an optoelectronic path. It is desirable for the method to decrease the electronic paths of the optoelectronic devices, thereby enhancing its performance. It is also desirable for the method to reduce the optical losses thereby increasing the efficiency of the optical interconnect. It is also desirable for the coupler to be simple and easily manufacturable. It would be of further advantage for the method to be simple, easily manufacturable, and cost efficient.